show Abstracthide AbstractEnterohaemorrhagic E. coli (EHEC) is a significant human pathogens that cause outbreaks of haemorrhagic colitis and haemolytic uremic syndrome. During infection, pathogens compete for iron with the host, and one mechanism by which EHEC obtains iron is through haem uptake and utilitisation which is encoded by the chu operon. We have demonstrated that the haem receptor chuA is regulated by the Crp-cAMP-dependent sRNA CyaR. We further demonstrate that activation of chuA by CyaR is independent of the chuA RNA-thermometer and termination by Rho. These results highlight the ability of regulatory sRNAs to integrate multiple environmental signals into a layered hierarchy of signal input. Overall design: Detecting rho-dependent transcripts in Escherichia coli str. O157:H7 str. Sakai